"I’m thinking of and praying for all those impacted by the shooting in Texas. In addition to offering my prayers and thoughts I also believe Congress must take action on gun violence," Casey wrote in two separate tweets.

In addition to offering my prayers and thoughts I also believe Congress must take action on gun violence (2/2)

The attack comes more than a month after the nation's deadliest mass shooting in modern history, in which a gunman opened fire on a country music festival in Las Vegas, killing 58 people and injuring hundreds more.

President Trump, who's embarking on a 12-day trip to Asia, tweeted shortly after reports of the shooting surfaced.

"May God be w/ the people of Sutherland Springs, Texas. The FBI & law enforcement are on the scene. I am monitoring the situation from Japan," Trump wrote.